Skip Navigation
Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed February 2008

What is the official name of the CTNS gene?

The official name of this gene is “cystinosin, lysosomal cystine transporter.”

CTNS is the gene's official symbol. The CTNS gene is also known by other names, listed below.

What is the normal function of the CTNS gene?

The CTNS gene provides instructions for making a protein called cystinosin. This protein is located in the membrane of lysosomes, which are compartments in the cell that digest and recycle materials. Proteins digested inside lysosomes are broken down into smaller building blocks, called amino acids. The amino acids are then moved out of lysosomes by transport proteins. Cystinosin is a transport protein that specifically moves the amino acid cystine out of the lysosome.

How are changes in the CTNS gene related to health conditions?

cystinosis - caused by mutations in the CTNS gene

More than 80 different mutations that are responsible for causing cystinosis have been identified in the CTNS gene. The most common mutation is a deletion of a large part of the CTNS gene (sometimes referred to as the 57-kb deletion), resulting in the complete loss of cystinosin. This deletion is responsible for approximately 50 percent of cystinosis cases in people of European descent. Other mutations result in the production of an abnormally short protein that cannot carry out its normal transport function. Mutations that change very small regions of the CTNS gene may allow the transporter protein to retain some of its usual activity, resulting in a milder form of cystinosis.

Where is the CTNS gene located?

Cytogenetic Location: 17p13

Molecular Location on chromosome 17: base pairs 3,636,468 to 3,663,103

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The CTNS gene is located on the short (p) arm of chromosome 17 at position 13.

The CTNS gene is located on the short (p) arm of chromosome 17 at position 13.

More precisely, the CTNS gene is located from base pair 3,636,468 to base pair 3,663,103 on chromosome 17.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about CTNS?

You and your healthcare professional may find the following resources about CTNS helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the CTNS gene or gene products?

  • Cystinosis
  • PQLC4

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding CTNS?

acids ; amino acid ; cell ; cystine ; deletion ; gene ; kb ; lysosome ; mutation ; protein

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Anikster Y, Shotelersuk V, Gahl WA. CTNS mutations in patients with cystinosis. Hum Mutat. 1999;14(6):454-8. Review. (
  • Bendavid C, Kleta R, Long R, Ouspenskaia M, Muenke M, Haddad BR, Gahl WA. FISH diagnosis of the common 57-kb deletion in CTNS causing cystinosis. Hum Genet. 2004 Nov;115(6):510-4. Epub 2004 Sep 9. (
  • Haq MR, Kalatzis V, Gubler MC, Town MM, Antignac C, Van't Hoff WG, Woolf AS. Immunolocalization of cystinosin, the protein defective in cystinosis. J Am Soc Nephrol. 2002 Aug;13(8):2046-51. (
  • Kalatzis V, Antignac C. Cystinosis: from gene to disease. Nephrol Dial Transplant. 2002 Nov;17(11):1883-6. Review. (
  • Kalatzis V, Nevo N, Cherqui S, Gasnier B, Antignac C. Molecular pathogenesis of cystinosis: effect of CTNS mutations on the transport activity and subcellular localization of cystinosin. Hum Mol Genet. 2004 Jul 1;13(13):1361-71. Epub 2004 May 5. (
  • NCBI Gene (
  • Servais A, Morinière V, Grünfeld JP, Noël LH, Goujon JM, Chadefaux-Vekemans B, Antignac C. Late-onset nephropathic cystinosis: clinical presentation, outcome, and genotyping. Clin J Am Soc Nephrol. 2008 Jan;3(1):27-35. doi: 10.2215/CJN.01740407. (
  • Touchman JW, Anikster Y, Dietrich NL, Maduro VV, McDowell G, Shotelersuk V, Bouffard GG, Beckstrom-Sternberg SM, Gahl WA, Green ED. The genomic region encompassing the nephropathic cystinosis gene (CTNS): complete sequencing of a 200-kb segment and discovery of a novel gene within the common cystinosis-causing deletion. Genome Res. 2000 Feb;10(2):165-73. (
  • Town M, Jean G, Cherqui S, Attard M, Forestier L, Whitmore SA, Callen DF, Gribouval O, Broyer M, Bates GP, van't Hoff W, Antignac C. A novel gene encoding an integral membrane protein is mutated in nephropathic cystinosis. Nat Genet. 1998 Apr;18(4):319-24. (
  • Wamelink MM, Struys EA, Jansen EE, Levtchenko EN, Zijlstra FS, Engelke U, Blom HJ, Jakobs C, Wevers RA. Sedoheptulokinase deficiency due to a 57-kb deletion in cystinosis patients causes urinary accumulation of sedoheptulose: elucidation of the CARKL gene. Hum Mutat. 2008 Apr;29(4):532-6. doi: 10.1002/humu.20685. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: February 2008
Published: February 8, 2016